Add campaign objects

[kyphii]

Implementation for campaigns / scenario packs in object format. These are all the campaign tabs from the current hardcoded implementation. "Other Parks" has been split into Official DLC, Competition Maps, and UCES pack, as the Other Parks will be utilized in game as a tab for loaded scenarios which are not grouped into a campaign.

Object properties were lifted from my proof of concept non-object implementation, and have been validated in-game via that POC. Translations have been copied over from the relevant StringIDs in the main repo translation files. JSON validity has been confirmed for all files.

One open question is how to handle category / difficulty headers. In my current implementation, these are derived from the scenario category values and displayed dynamically, same as the previous implementation. If we want the headers to instead be controlled by the campaign file, that data will need to be added here.